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Biomedical subjects

E Cohen

Publications and source records attributed to E Cohen.

At least 73 records · Page 4Linked to original sources
PubMed1999

A point mutation in the ethylene-inducing xylanase elicitor inhibits the beta-1-4-endoxylanase activity but not the elicitation activity.

Ethylene-inducing xylanase (EIX) elicits plant defense responses in certain tobacco (Nicotiana tabacum) and tomato cultivars in addition to its xylan degradation activity. It is not clear, however, whether elicitation occurs by cell wall fragments released by the enzymatic activity or by the xylanase protein interacting directly with the plant cells. We cloned the gene encoding EIX protein and overexpressed it in insect cells. To determine the relationship between the two activities, substitution of amino acids in the xylanase active site was performed. Substitution at glutamic acid-86 or -177 with glutamine (Gln), aspartic acid (Asp), or glycine (Gly) inhibited the beta-1-4-endoxylanase activity. Mutants having Asp-86 or Gln-177 also lost the ability to induce the hypersensitive response and ethylene biosynthesis. However, mutants having Gln-86, Gly-86, Asp-177, or Gly-177 retained ability to induce ethylene biosynthesis and the hypersensitive response. Our data show that the xylanase activity of EIX elicitor can be separated from the elicitation process, as some of the mutants lack the former but retain the latter.

Amino Acid Sequence↗
PubMed1999

Adolescent depressive symptoms as predictors of adult depression: moodiness or mood disorder?

OBJECTIVE: The authors' goal was to examine the relationship between subclinical depressive symptoms in adolescence and major depressive episodes in adulthood. METHOD: An epidemiologic sample of 776 young people received psychiatric assessments in 1983, 1985, and 1992. Among adolescents not meeting criteria for major depression, the authors estimated the magnitude of the association between subclinical adolescent depressive symptoms and adult major depression. RESULTS: Symptoms of major depression in adolescence strongly predicted an adult episode of major depression: having depressive symptoms more than two-standard-deviations above the mean in number predicted a two-fold to three-fold greater risk for an adult major depressive episode. CONCLUSIONS: Symptoms of depression in adolescence strongly predict an episode of major depression in adulthood, even among adolescents without major depression.

Adolescent↗
PubMed1999

Induced differentiation in HT29, a human colon adenocarcinoma cell line.

The human colon adenocarcinoma cell line HT29 displays an undifferentiated phenotype under standard growth conditions. When these cells were cultured for 21 days and then treated with forskolin, most of the cells formed brush borders on their apical surfaces. Brush border formation was inhibited by cytochalasin D but not by colchicine. Colchicine, nocodazole and taxol were found to induce differentiation and apoptosis in HT29 cells. Differentiation was characterized by flattening of the cells, formation of brush borders on apical surfaces and tight junctions between adjacent cells. Apoptosis was characterized by detachment of round cells from the cell layer, condensation of nuclear DNA and annexin V binding to cell surfaces. Treatment with colchicine or forskolin induced the association of E-cadherin to the cytoskeleton fraction of subconfluent HT29 cells. This effect was less prominent in post confluent cells. Our data indicate that microtubule-interfering agents may serve as an important tool in the study of differentiation and apoptosis in intestinal carcinoma.

Antineoplastic Agents↗
PubMed1999

From parallel to serial processing: a computational study of visual search.

A novel computational model of a preattentive system performing visual search is presented. The model processes displays of lines, reproduced from Wolfe, Friedman-Hill, Stewart, and O'Connell's (1992) and Treisman and Sato's (1990) visual-search experiments. The response times measured in these experiments suggest that some of the displays are searched serially, whereas others are scanned in parallel. Our neural network model operates in two phases. First, the visual displays are compressed via standard methods (principal component analysis), to overcome assumed biological capacity limitations. Second, the compressed representations are further processed to identify a target in the display. The model succeeds in fast detection of targets in experimentally labeled parallel displays, but fails with serial ones. Analysis of the compressed internal representations reveals that compressed parallel displays contain global information that enables instantaneous target detection. However, in representations of serial displays, this global information is obscure, and hence, a target detection system should resort to a serial, attentional scan of local features across the display. Our analysis provides a numerical criterion that is strongly correlated with the experimental response time slopes and enables us to reformulate Duncan and Humphreys's (1989) search surface, using precise quantitative measures. Our findings provide further insight into the important debate concerning the dichotomous versus continuous views of parallel/serial visual search.

Electronic Data Processing↗
PubMed1999

One lung ventilation: prospective from an interested observer.

The improvements in video endoscopic surgical equipment and a growing enthusiasm for minimally invasive surgical approaches, brought video assisted thoracoscopy (VAT) to the practice of surgery for diagnostic and therapeutic procedures. Most of these procedure required a well collapse lung and should be included in the absolute indication for one lung ventilation (OLV) category. The univent tube, is a novel means of achieving bronchial blockade. The bronchial blocker technique has been modified so that the bronchial blocker is passed along a single-lumen endobronchial tube. It was introduced to clinical practice to avoid the need to change the double lumen tube at the conclusion of the procedure. Finally, one of the most interesting future concept to keep adequate oxygenation during OLV, is the ability to modulate the lung circulation. In fact inhaled nitric oxide (NO) and intravenous Almitrine have been combined with additive effects on gas exchange. In case of OLV using that combination will maximize the HPV of the non-dependent lung while dilate the dependent lung to practically eliminate the transpulmonary shunt.

Anesthesia↗
PubMed1998

Telomeric repeats on small polydisperse circular DNA (spcDNA) and genomic instability.

Small polydisperse circular DNA (spcDNA) is a heterogeneous population of extrachromosomal circular molecules present in a large variety of eukaryotic cells. Elevated amounts of total spcDNA are related to endogenous and induced genomic instability in rodent and human cells. We suggested spcDNA as a novel marker for genomic instability, and speculated that spcDNA might serve as a mutator. In this study, we examine the presence of telomeric sequences on spcDNA. We report for the first time the appearance of telomeric repeats in spcDNA molecules (tel-spcDNA) in rodent and human cells. Restriction enzyme analysis indicates that tel-spcDNA molecules harbor mostly, if not exclusively, telomeric repeats. In rodent cells, tel-spcDNA levels are higher in transformed than in normal cells and are enhanced by treatment with carcinogen. Tel-spcDNA is also detected in some human tumors and cell lines, but not in others. We suggest, that its levels in human cells may be primarily related to the amount of the chromosomal telomeric sequences. Tel-spcDNA may serve as a unique mutator, through specific mechanisms related to the telomeric repeats, which distinguish it from the total heterogeneous spcDNA population. It may affect telomere dynamics and genomic instability by clastogenic events, alterations of telomere size and sequestration of telomeric proteins.

Animals↗
PubMed1998

[Nasopharyngeal colonization with Streptococcus pneumoniae in pediatric respiratory infections].

During the winter of 1995, nasopharyngeal colonization of Streptococcus pneumoniae was evaluated in 204 children with respiratory infection and 107 normal control children. There was no difference in gender or mean age between the groups, and no difference in carrier rate between sick (24.5%) and normal (22%) children (p = 0.6). Carrier rates were 19%, 32%, 31% and 17% at 6, 12, 24 and 48 months, respectively. Penicillin-resistant pneumococci (PRP) were found in 42% of sick and 16.6% of normal children, (p < 0.05). Resistance to more than 2 antibiotics was found in 28% of sick and in 12.5% of normal children. PRP were found in 67% and 34% of sick children with and without prior antibiotic treatment (p < 0.05). We conclude that there is no difference in the carrier rate of Streptococcus pneumoniae between sick and normal children. However, the high prevalence of PRP in children with respiratory infections is probably due to prior antibiotic treatment.

Carrier State↗
PubMed1998

The characterization of micro-organisms by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

A variety of gram-positive and gram-negative intact bacterial cells have been analysed by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and shown to provide fingerprint mass spectra with discrete peaks being observed over the mass range from 3 to 40 kDa. The spectra show both more peaks and peaks at a higher mass/charge ratio than have hitherto been reported for these micro-organisms and would appear to provide a profile of cellular proteinaceous material. The spectra are shown to be reproducible over variable time periods of up to three months and factors affecting reproducibility are discussed. The procedure, which requires minimal sample preparation, yields results in 30-40 minutes and allows visual identification of species- and strain-specific biomarkers for the characterization of the organisms. The importance of accurately defining sample preparation methodologies is central to the ability of the technique to generate reliable and reproducible data.

Bacterial Proteins↗
PubMed1998

Prophylaxis against soman inhalation toxicity in guinea pigs by pretreatment alone with human serum butyrylcholinesterase.

Human butyrylcholinesterase (HuBChE) has previously been shown to protect mice, rats, and monkeys against multiple lethal toxic doses of organophosphorus (OP) anticholinesterases that were challenged by i.v. bolus injections. This study examines the concept of using a cholinesterase scavenger as a prophylactic measure against inhalation toxicity, which is the more realistic simulation of exposure to volatile OPs. HuBChE-treated awake guinea pigs were exposed to controlled concentration of soman vapors ranging from 417 to 430 micrograms/liter, for 45 to 70 s. The correlation between the inhibition of circulating HuBChE and the dose of soman administered by sequential i.v. injections and by respiratory exposure indicated that the fraction of the inhaled dose of soman that reached the blood was 0.29. HuBChE to soman molar ratio of 0.11 was sufficient to prevent the manifestation of toxic signs in guinea pigs following exposure to 2.17x the inhaled LD50 dose of soman (ILD50, 101 micrograms/kg). A slight increase in HuBChE:soman ratio (0.15) produced sign-free animals after two sequential respiratory exposures with a cumulative dose of 4.5x ILD50. Protection was exceptionally high and far superior to the currently used traditional approach that consisted of pretreatment with pyridostigmine and postexposure combined administration of atropine, benactyzine, and an oxime reactivator. Quantitative analysis of the results suggests that in vivo sequestration of soman, and presumably other OPs, by exogenously administered HuBChE, is independent of the species used or the route of challenge entry. This assuring conclusion significantly expands the database of the bioscavenger strategy that now offers a dependable extrapolation from animals to human.

Animals↗
PubMed1998

Comparison of ketorolac and diclofenac in the treatment of renal colic.

OBJECTIVE: To compare the efficacy and adverse effects of ketorolac and diclofenac in the treatment of renal colic. METHODS: In a double-blind, randomized clinical trial, 57 patients admitted to the emergency room for renal colic, received either 30 mg of ketorolac or 75 mg of diclofenac i.m. (intramuscularly). Evaluations were performed at 1, 2 h and 6 h after treatment. Pain was assessed by a four-point verbal rating scale (VRS) and a visual analogue scale (VAS). Only patients with at least moderate pain according to the VRS were included. Seventy-five milligrams of pethidine i.m. was given as rescue medicine, if insufficient analgesia was achieved. The adverse effects recorded were sedation, nausea and vomiting. RESULTS: There was no significant difference between ketorolac and diclofenac, with respect to pain level over time, the number of patients requiring rescue medicine, or the level of adverse effects. CONCLUSION: Ketorolac and diclofenac are equally effective in the treatment of renal colic.

Adult↗
PubMed1998

Cytotoxic effects of arthropod venoms on various cultured cells.

The action of arthropod venoms is important to predators in search of prey and to humans as incidental victims or as a source for pharmacologically active compounds. Venoms from 30 arthropods (including 26 spider species) were assessed for cytotoxicity using cultured cells from one insect (Sf9) and three mammalian (murine neuroblastoma and macrophages and human osteosarcoma) sources. The most cytotoxic venoms to the four cell lines were from predatory jumping spiders (Salticidae, Phidippus sp.) and a centipede (Scolopenra sp.), with concentrations for 50% response of 1-8 microg venom per ml. The cytotoxicity of Phidippus ardens venom at these levels was instantaneous and evidenced by dramatic disruption of cell membranes resulting in cell collapse.

Animals↗
PubMed1998

Effects of prenatal morphine exposure on NK cytotoxicity and responsiveness to LPS in rats.

Prenatal exposure to opiates can adversely affect fetal development, resulting in long-term growth retardation and impairments in physiological and behavioral functions. In the present study we studied long-term effects of prenatal morphine exposure on immune functions, including the activity of natural killer (NK) cells and the febrile and behavioral responses to lipopolysaccharide (LPS). Pregnant Fischer 344 rats were given increasing doses of morphine in slow release emulsion during gestational days 12-18. Control rats were injected with vehicle and were either pair fed to morphine rats or fed ad lib. Postnatal experiments were conducted when offspring were 10-12 weeks old. Compared to both control groups, rats prenatally exposed to morphine exhibited: 1) suppressed cytotoxic activity of NK cells; 2) reduced LPS-induced fever measured by a biotelemetric system; 3) reduced hyperalgesia measured by the hot-plate test at 30 min, and augmented hypoalgesia at 2-6 h post-LPS; 4) higher open-field activity in saline-treated animals, and more pronounced suppression of activity in LPS-injected animals; 5) LPS-induced reduction of food consumption, body weight, and social exploration, which did not differ from the reduction observed in control animals. These findings indicate that prenatal exposure to morphine induces long-term impairment of host-defense mechanisms, which may render the offspring more susceptible to infectious diseases.

Analgesia↗
PubMed1998

Incidence of arrhythmias after thoracic surgery: thoracotomy versus video-assisted thoracoscopy.

PURPOSE: Atrial arrhythmias, especially supraventricular tachycardia (SVT) and atrial fibrillation, are common after thoracotomy and lung surgery. There are few existing data on the incidence of postoperative arrhythmias after video-assisted thoracoscopy (VAT). The purpose of the present investigation was to retrospectively determine the incidence of postoperative arrhythmias in patients who underwent VAT compared with those who underwent thoracotomy, and which factors are associated with an increased risk for arrhythmias in both groups. DESIGN: A retrospective investigation. SETTING: A metropolitan university hospital. PARTICIPANTS: The medical records of 124 patients who underwent thoracotomy and 81 patients who underwent VAT over a 2-year period were reviewed. MEASUREMENTS AND MAIN RESULTS: There was a 17% incidence of atrial arrhythmias after thoracotomy and 10% after VAT, but the difference was not statistically significant. In both groups, atrial fibrillation was the most common atrial arrhythmia. CONCLUSION: Patients receiving digoxin were at higher risk for postoperative arrhythmias. Patients older than 65 years were at risk for arrhythmias after thoracotomy and patients older than 80 years were at risk for arrhythmias after VAT. Patients who had postoperative arrhythmias had prolonged hospital stays compared with patients who did not have arrhythmias.

Adult↗